ChamplainView: Move the key-press event to view

Bind the key-press event to the view actor instead
of the kinetic_scroll actor. This will allow users
of GtkChamplainEmbed to use the pan and zoom bindings
from their application.

https://bugzilla.gnome.org/show_bug.cgi?id=738849
GtkChamplainEmbed: Propagate key-press to view

Make sure the GtkChamplainEmbed widget gives focus to the
GtkClutterEmbed widget. And also propagates the key press
events to the ChamplainView actor.

https://bugzilla.gnome.org/show_bug.cgi?id=738849
Whitespace change